Audio compressor for both RX and TX audio.

A compressor/limiter is a type of amplifier in which gain is dependent on the signal level passing through it. You can set the maximum level a compressor/limiter allows to pass through, thereby causing automatic gain reduction above some predetermined signal level, or threshold. Compression refers, basically, to the ability to reduce, by a fixed ratio, the amount by which a signal’s output level can increase relative to the input level. It is useful for lowering the dynamic range of a vocal, making it easier to be heard over the air without distortion.

For example, if you move around in front of the microphone during a QSO, making the output level vary up and down unnaturally. A compressor can be applied to the signal to help correct this phenomenon by reducing the louder passages enough to be compatible with the overall signal.

How severely the compressor reduces the signal is determined by the compression ratio and compression threshold. A ratio of 2:1 or less is considered mild compression, reducing the output by a factor of two for signals that exceed the compression threshold. Ratios above 10:1 are considered hard limiting.

As the compression threshold is lowered, more of the input signal is compressed (assuming a nominal input-signal level). Care must be taken not to over compress a signal, as too much compression destroys the acoustic dynamic response.

Limiting refers to the processing that prevents the signal from getting any louder (that is, it prevents any increase in the signal’s amplitude) at the output.

Vocals usually have a wide dynamic range. Transients (normally the loudest portions of the signal) can be far outside the average level of the vocal signal. Because the level can change continuously and dramatically, it is extremely difficult to ride the level with a console fader. A compressor/limiter automatically controls gain without altering the subtleties of the transmission.

The compressor has 6 setting sliders for:

Input Threshhold: Where the compressor should start kicking in level wise.

Ratio: Audio level reduction 1:1 to 1:12

Attack: Time before the compression kicks in

Release: Time to hold gain after the compression kicked in

Limiter: Extra limiter to limit output spikes

Output: Make up gain

The plug-in has an A/P switch for (A)ttached and (P)ass through

The compression can be done on RX audio and TX audio or TX audio only by selecting the R/T switch.

Left LED instrument shows Gain Reduction and Right LED instrument shows Output level.